Heat shock protein 90 alpha (Hsp90 alpha) is a cytosolic homodimeric molecular chaperone that modulates the stability and/or transport of a diverse set of critical cellular regulatory, metabolism, organization, and signaling proteins (1). Hsp90 distinguishes itself from other chaperones by having most of its known substrates as signal transduction proteins; e.g. non activated steroid hormone receptors, several proto-oncogenic tyrosine and serine/threonine kinases, and actin (2). These substrates are brought into complex by a multiprotein hsp90/hsp70-based chaperone machinery to function in protein folding (3). Two isoforms correspond to the major and minor isoform, Hsp90 alpha and Hsp90 beta. Hsp90 beta is expressed constitutively to a high level in most tissues and is generally more abundant than Hsp90 alpha, whereas Hsp90 alpha is stress-inducible and overexpressed in many cancer cells (4).